In order to encourage the sharing of ideas and creativity, countries often provide laws to protect ideas and expressions. Thus, a writer who composes a novel has rights in his work to facilitate him in exploiting his book. Without these rights, anyone could claim his work and sell it as their own. If this were allowed, the writer would not be as willing to publish his next novel. This, in effect, would curb public dissemination of valuable works for the good of all. The laws that govern the protection of such works generally have been around for many years. However, even if protective laws do exist, they must also be enforced in order for them to be effective. Typically, it is the enforcement process that often limits the value of a law. The intent to enforce may be genuine, but the ability to enforce may be lacking due to limits in technology.
Before the advent of the digital age, tracking of illegally copied goods generally rested on the ability to distinguish the genuine article from an illegal copy. Forensic techniques such as, for example, those relating to painting could be applied to a forged painting to determine its authenticity. With enough available evidence, it might even be possible to decipher who the forging artist is (such as by brush stroke technique, etc.). This type of detective work rests heavily on the availability of physical evidence. However, with the advent of the digital age, ideas and expressions are now reduced down to ones and zeroes, which are much easier to manipulate and duplicate. The digital aspect of these items permits exact duplicates of an original to be created. This typically can be accomplished with no indication whatsoever of which party actually did the copying.
Because of the ease of copying, techniques were developed to facilitate in making it easier to tell a digital original from a digital copy and/or where the digital information originated from. One such technique is to “watermark” a product. The term watermarking originally comes from a technique for marking paper. A paper watermark is usually visible only when the paper is held to a light source. A paper company would often use this technique to mark their name in the paper so that customers would be able to identify them as the maker of the paper. This technique has been modernized to facilitate in identifying the sources in digital (and analog) versions of items such as movies, photographs, and audio products.
The earliest versions of digital watermarking were very distinctive and often interfered with utilizing the product. For example, photographs would have the source printed directly across the photograph, affecting its aesthetics as a trade-off to protecting the object from being copied. This was often accomplished by utilizing a “layer” over the photograph in a digital imaging software product. Thus, in the digital realm, a party could also employ a software product to effectively remove these types of marks digitally. Thus, better ways of embedding the information in the digital data of the photographs have been developed in response to prevent easy removal of the watermarks.
However, despite the progression of digital watermarking technology, one of the drawbacks has been the lack of identifying sources from which parties illegally copy goods. Typically, a company will make multiple copies to disseminate to various distributors for distribution and/or use of the product. The originating company only intends for the product to be utilized as permitted within its legal rights and agreements with those parties that it disseminates its products to. Even if the originating company watermarks its product, illegally copied goods can only be traced back to the originating company. Often this is not, on its face, additional information. For example, a movie company producing a new movie with a distinct array of actors will know from the material itself that the movie originates from their company. Ideally, the originating company would like to know which authorized copy was employed to disseminate its product illegally. This would permit the company to take legal action against the guilty party who allowed the product to be copied. Technology utilized today permits various types of watermarking to be achieved, but with varying degrees of success. Often the watermark interferes with the use of a product. For example, one would not particularly enjoy watching a movie with a red watermark across the screen reading “distributed by company A.” Likewise, seemingly less intrusive technology often blurs images and/or interferes with the audio. To be effective, a technology must provide virtually undetectable incorporation of a watermark into a product, while still maintaining robust protection of the watermark itself. It must also permit the ability to distinguish between authorized copies in order to facilitate forensic analysis to determine sources of illegal copies. It is also significant that watermarks cannot be removed and/or impersonated by unauthorized parties; visible watermarks obviously do not fall into this category. This same problem also occurs when the watermark is perceptually invisible, but the watermarking algorithm does not have enough inherent secrecy (i.e., security).